Hydrocarbon conversion



y 1959 J. w. PAYNE 2,885,100

l-IYDROCARBON CONVERSION Original Filed Nov. 8, 1954 TI'TI Hi1" "iiin'mm I INVENTOR lav/@0424 v ATTORNEY United States Patent O HYDROCARBONCONVERSION John W. Payne, Woodbury, N.J., assignor to Socony Mobil OilCompany, Inc., a corporation of New York Application July 9, 1958,Serial No. 747,452

2 Claims. (Cl. 214-152) This invention relates to the conversion ofhydrocarbons by systems of the type which involve moving beds ofgranular contact material and more particularly to the use of thecontact material to maintain seals between Zones of difierent pressures.

In the cracking of hydrocarbons to produce an increased yield ofhydrocarbons boiling in the gasoline range it is customary to employ acontinuously moving bed of granular catalyst material. Succeedingportions of this material flow through a reactor in which the conversionof the hydrocarbon material takes place. During this reaction thecontact material becomes contaminated and provision is therefore made todeliver the moving bed to a regenerator wherein the contaminants areburned off. Succeeding portions of the regenerated contact material arethen returned to the reaction or conversion zone.

It is desirable that the hydrocarbon conversion take place underpressure and that the regeneration of the contact material take place atatmospheric pressure. Accordingly, the problem is presented ofcontinuously feeding contact material into a reaction zone whilemaintaining a positive pressure above atmospheric within that zone. Oneway to effect the seal is to use valves. These are, however,discontinuous in operation, expensive to install and maintain, anddamaging to the contact material. Accordingly, resort has been had tofeed legs of granular contact material which are long enough to maintaina head of contact material sufficient to keep the desired pressure levelwithin the reactor. Recently there has been a tendency to resort tohigher and higher pressures in the reaction zones and this creates arequirement for longer and longer feed legs in order to maintain theseals with an adequate factor of safety.

In an effort to overcome this problem, resort has been had to feed legscontaining zones of increased crosssectional area along their length.The presence of these zones reduces the length of feed leg required tohold any given pressure. The effect of the wide zone is to increase thestatic pressure of the gas being held back While reducing its dynamicpressure. This prevents the gas from reaching a bed disrupting velocityat the top of the bed of contact material. The actual volume of theintermediate zone of increased cross-section is, of course, dependentupon the pressure to be held and there must be maintained a suflicientamount of contact material above the plane where the gas falls below beddisrupting velocity to keep the bed density constant so that flowresistance will be stable. If these conditions are met, it is found thatthe length of the leg necessary to hold a given pressure may be reduced.

It has been found that the length of seal leg may be further shortenedif the material in the leg is compacted to increase its density.

It is an object of this invention to provide an improved cyclicallyoperable method for compacting the feed legs of a contact materialsystem so that a required pressure l atented May 5, 1959 drop may bemaintained with a shorter leg than in the case of uncompacted material.

It is further proposed according to the present invention to effect thecompressing of the contact material in a manner which avoids mechanicaldamage to its comapparent upon consideration of the following detaileddescription of a preferred embodiment thereof in conjunction with theannexed drawings wherein:

Figure 1 is a fragmentary view in elevation of a hydrocarbon conversionplant incorporating the present invention; and

Figure 2 is a view partially in elevation and partially in section of acontact material feed leg constituting a part of the system of Figure 1.

Referring now to the drawing in greater detail, the numeral 10designates a reactor in which hydrocarbons are treated in the presenceof granular contact material flowing continuously as a moving bedthrough a reaction zone generally designated at 11. Above the reactionzone there is a contact material receiving zone 12 which always containsenough contact material to maintain a continuously moving bed in thezone 11. The zone 12 is supplied with contact material from a series ofhoppers 13, 14 and 15. The hoppers 13, 14 and 15 are supplied withcontact material from hoppers 16, 17 and 18 which are locatedrespectively thereabove. The hoppers 16 to 18, inclusive, are suppliedthrough chutes 19, 20 and 21 from a contact material elevator 22, afragment of which is schematically illustrated in Figure 1. The elevator22 receives contact material from a regenerator, not shown, and itraises the material for delivery to the chutes 19, 20 and 21. The chutes19 to 21, inclusive, and the hopper 18 are open to atmosphere and henceatmospheric pressure prevails therein. On the other hand, the pressurewithin the reactor 10 is maintained at about 15 p.s.i.g. This being thecase, in order to maintain the pressure Within the reactor 10 againstleakage, it is necessary that the flow passage between zone 12 and thehoppers which feed it be of such density as to prevent substantialescape of fluid under pressure. With this thought in mind, elongatedtubular feed legs 23, 24 and 25 are connected between hoppers 13, 14 and15, respectively, and the zone 12. Similar tubular feed legs 26, 27 and28 connect the hoppers 16 to 18, inclusive, with the hoppers 13 to 15,inclusive.

While it is not a part of the present invention, it may be useful toexplain that zones 11 and 12 are separated by a plate 29 having tubes 30which pass therethrough. The tubes serve to carry the granular contactmaterial from the zone 12 to the zone 11. These tubes are of such size,number and distribution as to maintain a moving bed of contact materialin the zone 11 at all times. The volume of the zone 12 is such thatenough contact material is present to maintain the moving bed in thezone 11 during period when no flow of contact material is occurring inthe feed legs 23 to 25, inclusive.

Feed legs 23 to 28, inclusive, are mounted on resilient couplings forvibration. In Figure 2, feed leg 23 is drawn to an enlarged scale and itwill be described with the understanding that an identical constructionis used with all the feed legs 23 to 28, inclusive.

Below the hopper 13 there is a short resilient coupling section 31 whichis sufliciently flexible so that the conduit 23 can be vibrated ordisplaced without violation of the integrity of the conduit as a whole.A similar short section 32 is provided near the bottom of the conduit23. About midway of the length of the conduit there is mounted avibrator 33 which is electrically connected to a cycle timer 34 which isalso connected to vibrators 35, 36, 37, 38 and 39 which are mounted onpipes 24 to 28 inclusive in the same manner that vibrator 33 ismountedon conduit 23. Also connected to cycle timer 34 are valves 40, 41 and42, which are of the type to place the contents of the respectivehoppers 13, 14 and 15 in communication with atmosphere through shortstub pipes 43, 44 and 45 or in communication with the top of reactorthrough conduits 46, 47 and 48. Conduit 49 leadinginto the top ofreactor 10 is a sealing gas line.

In apparatus of the type to which the present invention relates, it iscustomary to introduce a sealing gas at a pressure very slightly abovethat prevailing in the reaction zone whereby any outward leakage ofcombustible hydrocarbon gases is avoided. One 'efiectofthe length or thecompactness of the seal legs such as 23 is the prevention of theexcessive loss of sealing gas. As a matter of fact, the loss of sealinggas along the leg can be used to determine the effectiveness of the sealmaintained.

The cycle timer 34 and the vibrators 33 and 35 to '39, inclusive, per seform no part of the present invention. The vibrators are of the readilyavailable commercial type and are attached to the conduit in a mannersuch that the vibrating pulsations are imparted to the conduit causingit to shake and so to shake its contents. Because of the fact that thevibrator is on the outside of the pipe, it has nomechanical contact withthe granular material and hence does not and cannot damage it in anyway. r

Furthermore, because the regeneration is conducted at high temperature,the contact material flowing through the various feed legs is quite hotand the necessary insulation ofthe vibrator is easily efiected becauseof its external location. The cycle timer is nothing more than a clockwith electric switches so arranged as to actuate the valves andvibrators in a sequence, the cycling of which will be apparent from thefollowing description of the operation of the apparatus.

It "is apparent that it is notnecessary that the cyclic operation bedone by an automatic machine since it can be done manually by anoperator if that be desired.

The use of three sets of feed hoppers to feed a single reactor is simplyforvthe purpose of material distribution across the cross-section of thezone 12. Thus, in describing the cycling operation of the apparatus,reference will be made to the system including hopper 16, feed leg 26,hopper l3, feed leg 23 and the associated valve 40 and vibrators 33 and37, with the understanding that the corresponding parts of the other twogroups of feed hoppers and legs are actuated at the same time.

For the purpose of beginning the description, let it be assumed that asupply of contact material has just been placed inzonelZ so that zonecan for a short time provide contact material for maintaining a movingbed in zone 11. At this stage the valve 40 is in the Figure 2 positionand no contact material is flowing in leg 26.

Under these circumstances, .the first step is to vibrate the leg 23 byactuation of the vibrator 33. This is followed by changing. valve 40from the Figure 2 full line to the Figure 2 broken line position. Oncethe hopper 13 has been treated through the conduit 43, material can anddoes flow through the leg 26 from the hopper 16 into the hopper 13. Thiscontinues until the hopper 13 is adequately filled, leg 23, having beencompacted by vibration, holds the pressure drop between the reactor 16and the hopper 1i. Atthat point, vibrator '37 is actuated to compact thematerial in leg 26 and thereafter valve 40 is restored to the full lineposition of Figure 2. This commences flow through the conduit 23refilling the zone 12 and causes the leg 26 to. hold epressure dropwhile hopper l is being filled from the chute 19. As was saidbeformwhile hopper 13 is being filled, hoppers 14 and 15 are alsobeingfilled and, when hopper 16 is being filled, so are hoppers 17 and.18.

A full cycle of the type just described takes only about r "was. all 1.

35 seconds. The hoppers are filled and emptied in about 10 seconds each.Pressurizing and depressurizing involving operation of the valves 40, 41and 42 takes about 5 seconds each and the vibrators are operated forabout 5 seconds at a frequency of 2000 to 8000.strokes per minute.[Examples of suitable vibrators are electric vibrators as manufacturedby the Syntron Company, Jeffry Manufacturing Company and Allis ChalmersManufacturing Company or pneumatic vibrators as manufactured by theCleveland Vibrator Company] It has been found in a catalyst feedsystemfor handling 75 tons an hour or 44.5 cubic feet a minute at atemperature of 1000 F. that the density in the legs after vibration is62.6 pounds per cubic foot as compared with 56.4 cubic feet in theunvibrated or loose packed leg. Fractional voids are reduced from .480cubic feet to .360 cubic feet as a result of vibrations. The pressure atthe top of the hopper is 14.7 p.s.i.a. and within the reactor it is189.7 p.s.i.a. A seal leg such as the 1eg23 shown in Figure 2 is 20 feetlong and 8 inches in diameter. By the vibratory compacting hereindescribed, seal gas requirements are reduced with respect to acomparable system without vibration from 2800 pounds per hour to 1620pounds per hour.

This application is a division of application, Serial Number 467,615,filed November 8, 1954.

I claim:

1. In a process for transferring solid material of palpable particulateform from one location to another the method comprising: maintaining asupply of the solid material in a supply zone, passing the solidmaterial downwardly from the supply zone through a confined passage as acompact gravitating column into a pressuring zone located therebelow,periodically removing solid material from said pressuring zone whileplacing said pressuring zone under an advanced gaseous pressure andsimultaneously vibrating the solid material in the confined passage tocompact the material in said passage, preventing disruption of thecompactness of the column and upward discharge of the solid materialfrom said passage by maintaining on top of said column of compactedmaterial in said supply zone a compact bed of said solid material ofsubstantially greater horizontal cross-sectional area than said columnin which gas escaping from said column decelerates, said bed being ofsufficient horizontal cross-sectional area and vertical depth to effectdeceleration of the gas to a. linear velocity below that which woulddisrupt the compactness of said bed substantially before it reaches thesurface of the bed, whereby a seal is maintained by virtue of thecompacted column of solid material preventing the escape of anysubstantial amount of gas from said pressuring zone.

2. A method for introducing solid material of palpable particulate forminto a high pressure zone comprising: maintaining a supply of the solidmaterial in a supply zone, gravitating the solid material downwardlyfrom the supply zone through a first confined passage as a compactgravitating column into a pressuring zone located therebelow,periodically raising the pressure in the pressuring zone andsimultaneously vibrating the solid material in the first confinedpassage to compact the material in the passage, preventing disruption ofthe compactness of the column and upward discharge of the solid materialfrom said passage by maintaining on top of said column of compactedmaterial in said supply zone a compact bed of said solid material ofsubstantially greater horizontal cross-sectional area than said columnin which gas escaping from said column decelerates below the beddisrupting velocity at a level substantially below the surface of thebed, while at the same time gravitating the solid material downwardlyfrom the pressuring zone through a second confined passage as a compactgravitating column into the high pressure zone located therebelow,periodically reducing the pressure in the pressuring zone andsimultaneously vibrating the solid material in the second confinedpassage to compact the material in the passage, preventing thedisruption of the compactness of the column and upward discharge of thesolid material from said passage by maintaining on top of said column ofcompacted material in said pressuring zone a compact bed of said solidmaterial of substantially greater horizontal cross-sectional area thansaid column,

in which gas escaping from said column decelerates below the beddisrupting velocity at a level substantially below the surface of thebed while at the same time gravitating solid material downwardly throughthe first passage to replenish the supply of solid material in saidpressuring zone.

No references cited.

1. IN A PROCESS FOR TRANSFERRING SOLID MATERIAL OF PALPABLE PARTICULATEFORM FROM ONE LOCATION TO ANOTHER THE METHOD COMPRISING: MAINTAINING ASUPPLY OF THE SOLID MATERIAL IN A SUPPLY ZONE, PASSING THE SOLIDMATERIAL DOWNWARDLY FROM THE SUPPLY ZONE THROUGH A CONFINED PASSAGE AS ACOMPACT GRAVITATING COLUMN INTO A PRESSURING ZONE LOCATED THEREBELOW,PERIODICALLY REMOVING SOLID MATERIAL FROM SAID PRESSURING ZONE WHILEPLACING SAID PRESSURING ZONE UNDER AN ADVANCED GASEOUS PRESSURE ANDSIMULTANEOUSLY VIBRATING THE SOLID MATERIAL IN THE CONFINED PASSAGE TOCOMPACT THE MATERIAL IN SAID PASSAGE, PREVENTING DISRUPTION OF THECOMPACTNESS OF THE COLUMN AND UPWARD DISCHARGE OF THE SOLID MATERIALFROM SAID PASSAGE BY MAINTAINING ON TOP OF SAID COLUMN OF COMPACTEDMATERIAL IN SAID SUPPLY ZONE A COMPACT BED OF SAID SOILD MATERIAL OFSUBSTANTIALLY GREATER HORIZONTAL CROSS-SECTIONAL AREA THAN SAID COLUMNIN WHICH GAS ESCAPING FROM SIAD COLUMN DECELERATES, SAID BED BEING OFSUFFICIENT HORIZONTAL CROSS-SECTIONAL AREA AND VERTICAL DEPTH TO EFFECTDECELERATION OF THE GAS TO A LINEAR VELOCITY BELOW THAT WHICH WOULDDISRUPT THE COMPACTNESS OF SAID BED SUBSTANTIALLY BEFORE IT REACHES THESURFACE OF THE BED, WHEREBY A SEAL IS MAINTAINED BY VIRTUE OF THECOMPACTED COLUMN OF SOLID MATERIAL PREVENTING THE ESCAPE OF ANYSUBSTANTIAL AMOUNT OF GAS FROM SAID PRESSURING ZONE.